Prior art balers generally have a bale forming chamber defined by an apron comprising an array of side-by-side belts, transverse slats trained on chains, a plurality of rolls or a combination of these various elements, e.g., rolls and belts. Crop material, such as hay, is picked up from the ground as the baler traverses the field, fed into a fixed or variable chamber where it is accumulated and compressed to form a cylindrical package of crop material. The formed package, while in its compacted condition inside the chamber, is wrapped with net, plastic film, twine or the like, to produce a completed round bale that is then ejected from the chamber onto the ground for subsequent handling.
Exemplary of prior art round balers of the type referred to above having a fixed chamber, i.e., a bale forming chamber that does not vary in size, are the various balers disclosed in U.S. Pat. No. 4,176,596, issued Dec. 4,1979 in the name of Hans O. Sacht, No. 4,212,149, issued Jul. 15, 1980 in the name of Bernard Krone et al, and 4,599,844, issued Jul. 15, 1986 in the name of Gerhard Clostermeyer et al, each of which illustrates a different type of apron assembly. In U.S. Pat. No. 4,176,596 a baler is disclosed in which the bale forming chamber is defined by a plurality of similar groups of side-by-side conveyor belts arranged around the periphery of the chamber. The conveyor comprises a pair of opposing chains between which a plurality of parallel crop engaging slats are mounted. The chamber in U.S. Pat. No. 4,212,149 is defined by a continuous slatted conveyor in combinations with a pair of floor rolls, in which an inner run of the conveyor is guided along a fixed path along a major portion of the periphery of the chamber. A third type of apron assembly, shown in U.S. Pat. No. 4,599,844, consists of a plurality of adjacent rolls arranged transversely in a generally circular array to define a cylindrical chamber.
Various wrapping systems employ known wrapping materials, such as net or twine, to wrap compacted packages of crop material formed in fixed chamber round balers. For example, the Sacht and Krone et al patents, mentioned above, refer to commonly accepted twine wrapping systems for completing bales formed in the balers disclosed. In another patent directed to a fixed chamber defined by transverse slats mounted on chains, U.S. Pat. No. 4,610,123, issued Sep. 9, 1986 in the name of Bernard Krone et al, a system is disclosed whereby net wrapping material is used. In this baler the net is introduced into the fixed chamber via the transverse inlet through which crop material is fed.
In the baler disclosed in the Clostermeyer et al patent, mentioned above, net wrapping is accomplished by introducing net into the forming chamber via a path between a pair of adjacent rolls in the circular array defining the chamber. Another example of this is illustrated in U.S. Pat. No. 4,580,398, issued Apr. 8, 1996 in the name of Dirk Bruer et al.
Although twine wrapped bales are common and readily acceptable, many farmers prefer to use net for various reasons, e.g., less losses in certain crop conditions, a smoother outer surface on the completed bale which gives added protection against rain, and reduced field time for wrapping due to the reduced number of revolutions of the completed package in comparison to twine wrapping. Regardless of the wrapping medium, in a fixed chamber baler, as in most variable chamber balers, initiation of the wrapping step is not commenced until a cylindrical package of crop material has been fully formed and compacted in the chamber at which time the tail of the twine or net is introduced to the chamber between the forming elements of the apron or through the crop inlet. The twine or net is retained between the outer surface of the compacted cylindrical package of crop material and the apron, and due to frictional force the wrapping material encases or encircles the package as it continues to rotate in the chamber. Finally, the wrapping process is completed, the net or twine is severed, and a completed bale is discharged from the chamber.
In the past, problems have been encountered in attempts to consistently introduce wrapping material to the chamber. Especially in the case of net where a tail of material the width of the package is desirably introduced simultaneously and evenly across the entire width of the forming chamber for efficient and effective wrapping. As mentioned above one of the principal advantages of net wrapping is the ability to reduce wrapping time. This is accomplished by limiting the number of revolutions of the completed package in the chamber during wrapping to 2 or 3 which is a significant contribution to reduction of the overall elapsed time in the bale forming process as compared to twine where ten times that number would not be uncommon, depending on crop material and bale size. However, a key to successfully achieving this important advantage is feeding an even tail into the chamber in a consistent and uniform fashion, and severing the net in a manner that enables subsequent wrapping to be initiated effectively.